Apparatus for liquid level measurement in a container

ABSTRACT

A liquid level measuring device for measuring the level of liquid in a storage or dispensing tank has an elongated tubular hollow body that carries a threaded coupler adapted for engaging a threaded nipple on top of the tank. A buoyant float is attached to a lower portion of the elongated body. The body slides in relation to the coupler while the coupler remains stationary in relation to the tank. As the liquid is dispensed from the tank, the buoyant float that was positioned on the surface of the liquid in the tank, lowers in relation to the tank, moving the elongated body into the tank. Measuring indicia placed en the exterior surface of the elongated body allows visual observation of the changing level of liquid in the tank.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a level measuring device, andmore particularly a device for measuring liquid levels in tanks, such asstorage tanks, liquid dispensing tanks and the like.

[0002] Many industries require storage of liquids and viscous liquids intanks during processing and dispensing. The oilfield industry usesdrilling mud for a variety of onshore and offshore operations. The drillmuds are usually stored in special tanks having a top opening for inputof the drill mud and an outlet in the bottom of the tank for dispensingof the mud as needed.

[0003] The viscosity of the drill mud and the chemical compositionthereof play an important role in the success of the drilling andcirculation operations. Some of the factors that need to be continuouslymonitored during dispensing is the viscosity of the mud, which may belighter or heavier, depending on the strata, rock formations, and otherconditions in a well bore. Some of the additives are relativelyexpensive and are added in small amounts. Other additives, such assynthetic oils may be added in larger amounts to facilitate drillingoperations.

[0004] Mud engineers and workers carefully monitor the content of thecirculation mud and the level of it in a mud tank. The mud tanks areusually made of steel. Sometimes expensive level measuring devices areused. More often, a mud engineer climbs to the top of the tank and peersinto the dark interior of the dispensing tank to roughly estimatewhether the mud is of the right viscosity and whether any additions arerequired.

[0005] Another method of making a rough estimate is to tap the side ofthe tank and try to guess by the reverberating sound how much mud isleft in the mud tank. The mud engineers often times have to guess howmuch mud is left in the stainless steel tank because there is nomeasuring indicia and no windows through which one can see the level ofliquid in the tank.

[0006] Sometimes the mud engineer has to supervise a number of suchtanks and, in inclement weather, climbing up and down to reach the deckwhere the tanks are positioned becomes a serious task, especially due tothe voluminous size of the tanks and difficulty of visual inspection.

[0007] The present invention contemplates elimination of drawbacksassociated with the current methods of determining the level in the mudtank and provision of an inexpensive, easy-to use device for measuringthe level of contents in a tank.

SUMMARY OF THE INVENTION

[0008] It is, therefore, an object of the present invention to provide adevice for measuring a level of liquid in a storage or dispensing tank.

[0009] It is another object of the present invention to provide alevel-measuring device that would allow an operator to determine thelevel of liquid left in the tank by visual observation from the exteriorof the tank.

[0010] It is a further object of the present invention to provide alevel-measuring device that is particularly adapted for use with mudtanks.

[0011] These and other objects of the present invention are achievedthrough a provision of an apparatus for measuring the level of liquid,which comprises an elongated hollow body having a floating membersecured on its lower end. The elongated body carries a coupler, withinwhich the body freely slides. A lower part of the coupler has innerthreads that are adapted to engage with the threads of a nipple securedon the top of the tank. The nipple has exterior threads; it is usuallycovered with a lid, or cap when the liquid is stored or dispensed. Theoutlet port of the tank is on the bottom of the tank.

[0012] An upper portion of the body is provided with a top cap. An upperpart of the coupler contacts a sliding stop that prevents the couplerfrom disengaging from the body. The stop has an inner opening with adiameter smaller than the size of the top cap.

[0013] The level measuring device is lowered into the tank with liquidsuch that the float member floats on top of the liquid. The coupler isthreadably engaged with the threads of the nipple after the lid has beenremoved from the tank. The body, which has a length approximating thedepth of the tank, gradually lowers into the tank by sliding through thestationary coupler. The body descends into the tank as the level ofliquid in the tank decreases.

[0014] The exterior surface of the body is provided with measuringindicia to allow an operator to visually observe the decreasing level ofliquid in the tank from the outside of the tank. If the level decreasestoo slow an operator may have to adjust the viscosity of the liquid.Conversely, if the tank empties too fast, the operator may need to addsolid additives to the mixture in the tank. If the liquid stops flowing,there may be an obstruction in the line that needs to be attended to.

[0015] The device of the present invention is easy to operate andinexpensive to manufacture. It does not require any modifications in theexisting tank structure, instead capable of accommodating all types ofstorage and dispensing tanks.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Reference will now be made to the drawings, wherein like partsare designated by like numerals and wherein,

[0017]FIG. 1 is a perspective view of the level-measuring device inaccordance with the present invention positioned in a tank full ofliquid.

[0018]FIG. 2 is a perspective view of the level-measuring device of thepresent invention positioned in a tank when the liquid level hassubstantially decreased.

[0019]FIG. 3 is a perspective, partially cut away, exploded view of themeasuring device in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0020] Turning now to the drawings in more detail, numeral 10 designatesthe level measuring device in accordance with the present invention. Thedevice 10 comprises an elongated tubular body 12 that is slightlygreater in length than the depth of a storage and dispensing tank 14.The top of the body 12 is provided with a top cap 16 that closes the topopening of the hollow body 12. The bottom of the body 12 carries aflotation member, or float 18, which is securely connected to the body12. The float 18 has a generally cylindrical main body and afrustoconically-shaped upper collar 20. The collar 20 may engage thelower part of the body 12 by friction or may be threadably engageablewith the body 12, if desired.

[0021] The storage and dispensing tank 14 may have a square orrectangular configuration, depending on the type used in a particularindustry. Conventional storage tanks for mud used in the oilfield areprovided with a top opening 22 and a bottom outlet port 23. A dispensinghose 25 is connected to the port 23 for dispensing of liquid from thetank 14.

[0022] The top opening 22 is surrounded with an exteriorly threadednipple (not shown), which is closed with a lid (not shown) when the tank14 is in transportation or in a conventional dispensing mode. The device10 of the instant application is designed to be operationally connectedto the exteriorly threaded nipple of the tank 14. To this end, thedevice 10 is provided with a coupler 24 of a generally cylindricalconfiguration. The lower part of the coupler 24 is provided withinterior threads 26. The threads 26 engage with the threads of thenipple of the tank 14 and secure the coupler 24 on top of the tank 14.

[0023] A through opening 28 formed in the coupler 24 has a diametergreater than the exterior diameter of the body 12, such that the body 12freely slides within the opening 28 of the coupler 24. An upper portion30 of the coupler 24 has a smooth interior wall without threads. Theupper portion 30 is provided with a plurality of through openings 32,which serve as vents to allow escape of gases from the tank 14 when thelevel measuring device 10 is positioned thereon.

[0024] A stop member 34 is slidably mounted on the body 12 above thecoupler 24. The stop member 34 has a substantially cylindrical upperpart 36 and a reduced diameter lower part 38. A central through opening40 is formed through the body of the stop member 34. The opening 40 hasa diameter smaller than the exterior diameter of the cap 16. Theexterior diameter of the upper part 36 of the stop member 34 issubstantially equal to or greater than the exterior diameter of theportion 30 of the coupler 24. The stop member 34 serves as a means forlimiting sliding movement of the body 12 in relation to the stationarypositioned coupler 24.

[0025] The lower cylindrical part 38 of the stop member 34 fits into theopening 28 of the coupler. An annular shoulder 29 formed between theupper part 36 and the lower part 38 of the stop member 34 contacts thetop edge 33 of the coupler 24. A lower edge 35 of the stop member 34contacts an upper edge 21 of the float 18 when the device 10 ispositioned in a tank 14, which is full with mud or other liquid.

[0026] The exterior surface of the body 12 is provided with measuringindicia 42 (see FIGS. 1 and 2) that helps the user in determining thelevel of liquid in the tank 14. The measuring indicia 42 may becalibrated to reflect the liquid level in barrels, liters or gallons,depending on the particular requirements in the industry.

[0027] In operation, the user engages the threaded coupler 24 with theexterior threads of the nipple on top of the tank 14. The measuringdevice 10 is thereby detachably secured on top of the tank 14. The float18 extends into the interior 44 of the tank 14, wherein liquid, such asmud and the like is deposited up to a desired level 46. As the fluid 46is being consumed or drained, the body 12, sliding within the stopmember 34 and the coupler 24, gradually lowers into the interior 44 ofthe tank 14.

[0028] The mud engineer or other operator can observe the decreasinglevel of fluid in the tank 14 by observing how much the body 12 isexposed above the tank 14 and above the stop means 34. FIG. 2illustrates position of the device 10 when the tank is almost empty,with the liquid level 48 being adjacent to the bottom 50 of the tank 14.Therefore, instead of tapping on the side of the tank or peering intothe dark enclosure of the tank 14, as was done with conventionalmethods, the operator can easily determine when the fluid in the tank 14reaches the level requiring replenishment.

[0029] By calibrating the body 12 with desired indicia 42, the operatorcan determine with a certain degree of precision when the supply in thetank 14 is close to being exhausted.

[0030] The device 10 may be made of any non-corrosive material suitablefor technological field where the device 10 is to be used. For use withmud fluids, the device 10 may be made of polyvinyl chloride plastic(PVC). The device 10 is lightweight and can easily float on the surfaceof a viscous or nonviscous fluid. The hollow body 12, as well as thefloat 18 help the device 10 to stay on top of the liquid level in thetank 14 without submerging.

[0031] If desired, the threaded nipple on top of the tank may be fittedwith a plastic threaded sleeve with a rifle-type barrel to keep thefloating body 12 in a secure position in relation to the nipple and toavoid the metal to plastic connection that may weaken with use.

[0032] The vent openings 32 are important because the tank 14 is beingdrained as the fluid is dispensed through the conduit 25. It is possibleto create vacuum in the tank and cause collapse of the tank body unlessthe vent holes allow circulation of air between the exterior of the tank14 and the interior thereof.

[0033] The top cap 14, which closes the interior of the body 12 preventsrain or ocean water from getting into the interior of the tank 14. Theobservation of the level of liquid being dispensed from the tank 14 maybe done from an enclosed environment, such as a deck structure thatprotects the mud engineer from elements.

[0034] The device 10 also assists the operator in determining whetherthe consumption of the fluid inside the tank has taken place or not. Ifsuddenly the body 12 stops moving down in relation to the coupler 24, itwill serve as a good indication that there is a stoppage somewhere downthe line that needs to be attended to

[0035] Many changes and modifications can be made in the design of thepresent invention without departing from the spirit thereof. I thereforepray that my rights to the present invention be limited only by thescope of the appended claims.

I claim:
 1. An apparatus for determining the amount of liquid in a tank,the tank having a top opening surrounded with an exteriorly threadednipple, the apparatus comprising: an elongated hollow body; a couplerthreadably attachable to the threaded nipple, said coupler having aninterior opening extending therethrough for slidably receiving the bodytherein; a buoyant member fixedly secured on a lower portion of saidbody, said buoyant member extending into said tank when said coupler isengaged with said nipple, said body moving in relation to said tank inresponse to displacement of said buoyant member caused by a change in alevel of liquid in the tank.
 2. The apparatus of claim 1, wherein a topportion of said body carries a top cap closing an open top end of saidhollow body.
 3. The apparatus of claim 2, further comprising a means forlimiting slidable movement of said body in relation to said coupler,said means comprising an annular collar slidably positioned between saidcoupler and said top cap, said collar having an interior opening with adiameter smaller than the exterior size of said top cap and an exteriordiameter substantially equal to or greater than an exterior diameter ofsaid coupler.
 4. The apparatus of claim 3, wherein said annular collarcomprises an upper part and a reduced diameter lower part, and wherein ashoulder is formed about the line of connection between the upper partand the lower part, said shoulder resting on a top edge of said couplerwhen the apparatus is oriented vertically to extend at least in partinto said tank.
 5. The apparatus of claim 3, wherein said annular collarcomprises an upper part and a reduced diameter lower part, and whereinsaid lower part contacts an upper edge of said buoyant member when theelongated body is positioned in a tank with a high liquid level, saidannular collar gradually moving away from said buoyant member as theliquid level in the tank decreases.
 6. The apparatus of claim 1, whereinsaid coupler comprises an internally threaded lower portion and an upperportion unitary connected to the lower portion, said upper portion beingprovided with a plurality of through openings formed in the annular wallthereof to permit air circulation between the interior of the tank andan exterior thereof.
 7. The apparatus of claim 1, wherein said body hasa length substantially equal to or greater than the depth of said tank.8. The apparatus of claim 1, wherein said body is provided with ameasuring indicia on an exterior surface thereof to allow visualobservation of the level of liquid left in the tank.
 9. An apparatus fordetermining the amount of viscous fluid in a dispensing tank, the tankhaving a top opening surrounded with an exteriorly threaded nipple, theapparatus comprising: an elongated hollow body; a coupler threadablyattachable to the threaded nipple, said coupler having an interioropening extending therethrough for slidably receiving the body therein,said coupler comprising an internally threaded lower portion and anupper portion unitary connected to the lower portion, said upper portionbeing provided with a plurality of through openings formed in theannular wall thereof to permit air circulation between the interior ofthe tank and an exterior thereof; and a buoyant member fixedly securedon a lower portion of said body, said buoyant member extending into saidtank when said coupler is engaged with said nipple, said body moving inrelation to said tank in response to displacement of said buoyant membercaused by a change in a level of viscous fluid in the tank.
 10. Theapparatus of claim 9, wherein a top portion of said body carries a topcap closing an open top end of said hollow body.
 11. The apparatus ofclaim 10, further comprising a means for limiting slidable movement ofsaid body in relation to said coupler, said means comprising an annularcollar slidably positioned between said coupler and said top cap, saidcollar having an interior opening with a diameter smaller than theexterior size of said top cap and an exterior diameter substantiallyequal to or greater than an exterior diameter of said coupler.
 12. Theapparatus of claim 11, wherein said annular collar comprises an upperpart and a reduced diameter lower part, and wherein said lower partcontacts an upper edge of said buoyant member when the elongated body ispositioned in a tank with a high level of viscous fluid, said annularcollar gradually moving away from said buoyant member as the level ofthe viscous fluid in the tank decreases.
 13. The apparatus of claim 9,wherein said elongated body is provided with a measuring indicia placedon an exterior surface of said elongated body to allow visualobservation of a decreasing level of the viscous fluid in said tankcaused by dispensing of the viscous fluid from said tank.
 14. Theapparatus of claim 9, wherein said elongated body has a length at leastas great as the vertical dimensions of said tank.
 15. A method ofmeasuring level in a tank having a top opening and a threaded collarsurrounding said top opening, the method comprising the following steps:providing an elongated hollow body, a coupler threadably attachable tothe threaded collar, said coupler having an interior opening extendingtherethrough for slidably receiving the body therein, and a buoyantmember fixedly secured on a lower portion of said elongated body;providing measuring indicia on an exterior surface of said elongatedbody corresponding to units of liquid measure; attaching said coupler tosaid collar, while positioning said buoyant member in an interior ofsaid tank such that the buoyant body floats on the surface of liquid inthe tank; visually observing movement of said elongated body into theinterior of said tank caused by a decreasing level of liquid in saidtank.
 16. The method of claim 15, further comprising the steps ofproviding vent opening in said coupler to permit circulation of gasesbetween the interior of said tank and the exterior thereof.
 17. Themethod of claim 15, wherein a top portion of said body carries a top capclosing an open top end of said hollow body and wherein a stop means forlimiting slidable movement of said body in relation to said coupler arecarried by said elongated body.
 18. The method of claim 17, wherein saidstop means comprises an annular collar slidably positioned between saidcoupler and said top cap, said collar having an interior opening with adiameter smaller than the exterior size of said top cap and an exteriordiameter substantially equal to or greater than an exterior diameter ofsaid coupler.